The present invention relates to disc drive storage systems, and more particularly to an improved air bearing slider for use with a rotary actuator in a disc drive.
Information storage technology and the storage capacity available therefrom has been historically limited by a number of factors. A typical prior art Winchester magnetic storage system includes a magnetic head that has a slider element and a magnetic read/write element and is coupled to a rotary actuator magnet and coil assembly by a suspension actuator arm so as to be positioned over the surface of a spinning magnetic disc. In operation, lift forces are generated by aerodynamic interaction between the magnetic head and the spinning magnetic disc. The lift forces are opposed by spring forces applied by the suspension so that a predetermined flying height is hopefully maintained over a full radial stroke of the radial actuator assembly above the surface of the spinning magnetic disc. Such conventional magnetic heads are constrained by the theoretical limit on the ability to closely pack adjacent magnetic bits on the disc surface and still accurately recover and read each bit of information.
To address this problem, much research is being done in the development of magneto-optical (MO) storage technology which provides a higher areal density. During conventional writing of information in MO disc drives, an incident laser beam heats a selected spot of interest on the MO disc to approximately the Curie point. A time varying vertical bias magnetic field is used to define a pattern of xe2x80x9cupxe2x80x9d or xe2x80x9cdownxe2x80x9d magnetic domains in a recording layer. Subsequently, as the selected spot of interest cools, information is recorded on the MO disc. The size of the magnetic field that is generated provides a lower limit on a maximum data density that may be recorded on the MO disc. Information access in the MO storage system in turn is limited by the size of the optical spot to which an incident laser beam may be focused on the disc surface. Magneto-optical information access requires the use of polarized laser light for reading and writing information on an MO disc. To read information, MO technology makes use of a magneto-optical effect (Kerr effect). To detect a modulation of polarization rotation imposed on the linearly polarized incident laser beam by the recorded domain marks in the recording layer. The polarization rotation (representing the information stored at recorded marks or in the edges of the recorded marks) is embodied in a reflection of the linearly polarized laser beam and is converted by optics and electronics for readout.
It is apparent that an important factor in the ability to accurately read and write information from an MO disc, as well as to rapidly access different storage tracks on the MO disc is the design of the flying head, which carries the various components required for accessing magneto-optical information. The illumination of a memory location on the disc by a very fine spot size is essential to the system operation.
However, the spot is projected through a very small opening in a coil or lens holder onto the disc. This opening, over time, may collect dirt or other particles which would diffuse or obscure the light spot. This is because the slider, which is the primary part of the flying head which controls the flying characteristics, typically includes a pair of side rails which are positioned along its side edges and are disposed about a recessed area. These side rails form a pair of air bearing surfaces. The part of the optics assembly which directs the light beam onto the disc is located behind one side rail. As the disc rotates, the disc drags air under the slider and along the air bearing surfaces in a direction approximately parallel to the tangential velocity of the disc. As the air passes beneath the side rails, the compression by the air bearing surfaces causes air pressure between the disc and the air bearing surfaces to increase, which creates a hydrodynamic lifting force that causes the slider to lift and fly above the disc surface. Since the small particles and other contaminants tend to follow the air bearing flow field, they could enter the region behind the air bearing surface and be brought into contact with the path along which the light beam travels, clouding or clogging the path.
Therefore, a basic object of the invention is to provide an air bearing slider which has improved utility in an MO disc.
A related objective of the invention is to provide an air bearing slider which is especially useful for data access in a magneto-optical storage system.
A further objective of the invention is to provide an air bearing slider (ABS) which has improved access to the data stored in a disc storage system by providing a clear path for light to the disc, free of the light being obscured by debris and other contaminants.
Yet another objective of the invention is to provide an air bearing slider which includes means for shaping the air flow path to divert dirt and contaminants from the light path.
These and other objectives for the air bearing slider design are achieved by utilizing a slider which mounts the output section of the optics behind one slider rail in a unique fashion to shape the air flow path past the optics assembly output section. The output optics are normally mounted on a rectangular platform of about the width of a rail, as improved herein, the optics are mounted on a platform which is a semi-circle, with the curve facing that rear of the rail but separated by a gap. The curved platform diverts the air flow which fills in behind the slider rails, with the majority of the air flow passing beside the platform so that few contaminants can impede the optical path.
Other features and advantages of the present invention will be better understood by reference to the following figures and the detailed description of an exemplary embodiment given below in conjunction with these figures.